Signaling by electromagnetic waves.



No 730,753. PATENTED JUNEVQ, 190s.

' R. A. FESSENDEN.

SIGNALING BY ELECTROMAGNETIC WAVES. APPLICATION rmm APR. 9, 1903.

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UNITED STATES Patented June 9, 1903.

PATENT OFFICE.

REGINALD A. FESSENDEN, OF PITTSBURG, PENNSYLVANIA.

SIGNALING BY ELECTROMAGNETIC WAVES.

'SZECIFICATION forming part of Letters Patent No. 730,753, dated June 9,1903. Application filed April 9, 1903. Serial No. 151,868. (No modelJ Toall, whmn it may concern.-

Be it known that I, REGINALD A. FEssEN- DEN, a citizen of the UnitedStates, residing at Pittsburg, in the county of Allegheny and State ofPennsylvania, have invented or discovered certain new and usefulImprovements in Signaling by Electromagnetic Waves, of whichimprovements the following is a specification.

' The invention herein described relates to certain improvements in thetransmission of energy by electromagnetic waves.

It relates more particularly to the transmission of signals byelectromagnetic waves, either telegraphic or telephonic.

It relates more particularly still to improvements in the methods andapparatus described in United States Patents Nos. 706,735, 706,736,706,737, 706,747, and 727,325.

Heretofore in the practice of the art of wireless telegraphy when acontinuous current has been employed as a means of producingelectromagnetic radiation it has been used to excite an induction-coiland a mechanical break or its substantial equivalent, a Wenheldtinterrupter, has been employed. This method is disadvantageous forthereason that any desired number of discharges per second cannot beobtained for mechanical and other reasons, and in addition in the caseof the Venheldt break the action is not uniform. For these reasons ithas been difficult to obtain a substantially continuous stream ofelectromagnetic radiation, such as-is adapted to be used with a cumulatively-acting receiver or with a telephonic transmitter-as,forexample, those shown in Figure 10, United States Patent No. 706,742. Inaddition the lack of ability to produce any desired number of dischargesper second has rendered it difficult to carry out the method of grouptuning described in United States Patents Nos. 706,742 and 727,325-t'.e., sending out groups of waves of predetermined group frequency andoperating thereby a receiver tuned mechanically or electrically to thegroup frequency.

By means of the apparatus herein described I am enabled to obtain from acontinuouscurrent source any desired number of discharges per secondacross a discharge-gap used in the production of electromagnetic waves.

In the accompanying drawing, forming a part of this specification, thefigure is a diagrammatic view illustrating the invention.

In the drawing, 1 is the sending-conductor, shown connected to ground.

2 is the discharge-gap.

12 is a capacity.

l3 isaself-inductance,preferably variable.

57 is a continuous-current dynamo.

In the particular arrangement herein shown and described thecontinuous-current source should be one of constant voltage. When usingsuch form of generator, a high resistance 59, preferably having alowinductance, is in series in the sending-circuit. Any suitable means, asa plug 60, for shunting a part of the resistance is preferably employedfor cutting out more or less of the resistance. In operation the dynamocharges the condenser 12 in the circuit 12 13, and when the potentialhas risen sufficiently a discharge across the spark-gap will occur,discharging the condenser and setting up oscillations in thesending-conductor. On account of the high resistance 59 some time isrequired to recharge the condenser to sparking potential. Hence thedischarge is intermittent and may be made to occur as many times persecond as desired by plugging out more or less of the resistance, and soto give any desired number of discharges per second.

Though I have herein described more particularly my invention inconnection with a continuous-current source having constant voltage, Ido not, however, limit myself to the use of a constant-voltage source ofcontinuous current, because I believe myself to have been the first touse continuous currents directly for the production of electromagneticradiation,and more particularly for electromagnetic Wave-signaling,without the necessary use of an induction-coil or inductioncoil break.

It is characteristic of my invention that on account of the fact that nobreak is used there is no necessary appreciable interval of time betweenthe acts of charging and of discharging, as is the case when aninduction coil or break is used.

Though a constant-voltage source of continuous current is herein moreparticularly described .and shown, a CODStEtDt-CHII'OHIZ source ofcontinuous current may be used if certain improvements and modificationsare made to adapt it for purposes of wireless telegraphy. Thesenecessary improvements and modifications are not, however, shown orclaimed here.

I am aware that a source of continuous current has been used previouslywithout a mechanical break to generate electromagnetic waves. I refer tothe use of the Wenheldt break. This apparatus, however, was employed soas to perform exactly the same function as the ordinary mechanicalbreak, was placed in the same positiont'. 6., in the primary circuit ofthe induction-coiland operated to break or open the primary circuit ofThe induction-coil in the same manner as the mechanical break. Its usetherefore consisted in substituting one form of inductioncoil break foranother form without altering their functions, both forms of breakinterrupting the circuit of the source of voltage. This use thereforediffers entirely in principle from the method contemplated by me, forthough the Wenheldt break may be used by virtue of the fact that it iscapable of functioning as a discharge-gap its use as a break for aninduction-coil is not within the limits of my invention.

I am also aware that highly oscillatory currents have been obtained froma direct-current source by Elihu Thomson, United States and it has not,so far as I am aware, been used for wireless-telegraphic purposes, norcould it be so used without certain important additions, improvements,and modifications. It diifers in the fact that in the patent abovereferred to the high-frequency oscillations are obtained by using acircuit in which the current is maintained constant, the method in whichthis constant current is obtained not being essential so long as it isconstant, and

this constant current is swung from side to side, so that a portion ofit passes alternately through the circuit in which the oscillations areproduced and across a discharge-gap. In the method herein moreparticularly described, though I do not limit myself to this particularmethod, the source of voltage is maintained constant and the current isarranged so that it is not constant, but fluctuates. Again, intheThomson method above referred to the amount of current whichoscillates from side to sidet'. 6., from the discharge-gap to theoscillating circuit and back again-is that required to charge theoscillating circuit. This amount will vary with the potential across theoscillating circuit, and this again will vary with the value of the meanresistance of the spark-gap. Gonsequentlyif this mean resistancevariesfor example, on account of the terminals becoming heated-theperiodicity of the oscillating discharge will vary. On the other hand,in my method herein described the periodicity is independent of the meanvalue of the resistance of the discharge-gap and depends upon thedischarge voltage. Again, in the Thomson method described above, sincethe voltage which operates across the oscillating circuit is not thedirect voltage of the direct-current generator, but theinductive voltagodue to the large self-induction used, it is difficult to make and breakthe circuit after the manner commonly used in wireless telegferred tothe oscillation frequency is necessarily identical with the dischargefrequency, and this is not always advisable for wireless telegraphy,where it is sometimes'advisable to have a group frequency in addition toa wave frequency. Lastly, in the device shown in the Thomson patentabove referred to there is no means shown for effecting the radiation ofelectrical waves, and though systems of wireless telegraphy have beenpublicly experimented with for seven or eight years the device abovereferred to has not been applied to this purpose, from which it isbelieved that experimenters who may have tried this method have foundthat though admirably adapted for operating the devices in connectionwith which it is shown it was yet not obvious or true that it furnisheda suitable means for generating electromagnetic waves or could be usedfor telegraphic purposes.

It is characteristic of the particular form herein shown that when thedischarge-gap circuitsthat is, the circuits of which the discharge-gapforms a portionare discharged that the points between which the maximumdifierence of potential exists are shifted. For example, before thedischarge the maximum potential is across the discharge-gap, whiletoward theclose of the discharge the maximum difference of potential isacross the resistance 59. I

What I claim is 1. In a system of signaling by electromagnetic waves,the combination of a radiatingconductor, a source of continuous currentand means for charging the conductor without interrupting the source ofvoltage.

2. In a systemof signaling by electromagnetic waves, the combination ofa radiatingcon'ductor, a source of practically-constant voltage andmeans forcharging the conductor without interrupting the source ofvoltage.

3. In a system of signaling cy-electromagnetic waves, the combination ofa radiatingconductor, a source of continuous current and means forcharging and discharging the conductor without disconnecting the sourceof voltage.

4. In a system of signaling by electromagnetic waves, the'combinationofa radiatingconductor, a source of practically-constant voltage and meansfor charging and discharging the conductor without disconnecting thesource of voltage.

5. In a system of signaling by electromagnetic waves, the combination ofa vradiatingconductor, a source of continuous current and means forcharging and discharging the conductor without changing the electricalconnection of the circuits.

6. In a system ofsignaling by electromagnetic waves, the combination ofa radiatingconductor, a source of practically-constant voltage and meansfor chargingand discharging the conductor without changing theelectrical connection of the circuits.

7. In a system of signaling by electromag netic waves, the combinationof a radiatingconductor, asource of continuous current and means forcharging the conductor after discharging without interrupting the sourceof voltage.

8. In a system of signaling by electromagnetic waves, the combination ofa radiatingconductor, a source of practically-constant voltage and meansfor charging the conductor after discharging without interrupting thesource of voltage.

9. In a system of signaling by electromagnetic waves, the combination ofa radiatingconductor, asource of continuous current and means forcharging the conductor after each discharge without interrupting thesource of voltage.

10. In a system of signaling by electromag netic waves, the combinationof a radiatingconductor, a source. of practically-constant voltage andmeans for charging the conductor after each discharge withoutinterrupting the source of voltage.

11. In a system of signaling by electromagnetic waves, the combinationof a radiating conductor, a source of continuous current and electricalmeans for charging and discharging the conductor.

12. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a source of practically-constant voltage andelectrical means for charging and discharging the conductor.

13. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a source of continuous current, electricalmeans for charging and discharging the conductor at a rate determined bythe electrical constants of the circuits.

14. In a system of signaling by electromagnetic Waves, the combinationof a radiatingconductor, a source of practically-constant voltage,electrical means for charging and discharging the conductor at a ratedetermined by the electrical constants of the circuits.

15. In a systeniof signaling by electromagnetic waves, the combinationof a radiatingconductor, a source of continuous current and electricalmeans for controlling the periodicity of charging of theradiating-conductor.

16. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a source of practically-constant voltage, andelectrical means for controlling the periodicity of charging of theradiatingconductor.

17. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a source of continuous current, a dischargegap,and means for electrically shifting the position of maximum diiferenceof potential in the circuit.

18. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a source of practically-constant voltage, adischarge-gap, and means for electrically shifting the position ofmaximum difference of potential in the circuit.

19. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a source of continuous current and means forelectrically shifting the position of maximum difference of potential inthe circuit. v

20. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a source of practically-constant voltage andmeans for electrically shifting the position of maximum difference ofpoten-' tial in the circuit.

21. In a system ofsignaling by electromagnetic waves, the combination ofa radiatingconductor operatively connected to a discharge-gap, a sourceof continuous current, and means for charging and discharging thedischarge-gap circuitwithout an appreciable time interval betweencharging and discharging.

22. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor operatively connected to a discharge-gap, asource of practically-constant voltage, and means for charging anddischarging the discharge-gap circuit without an appreciable timeinterval between charging and discharging.

23. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor operatively connected to a discharge-gap, aconstantly-responsive receiver a source of continuous current, and meansfor charging and discharging the dischargegap circuit without anappreciable time interval between the charging and discharging.

24. In a system of signaling by electromagnetic Waves, the combinationof a radiatingconductor operatively connected to a discharge-gap, aconstantly-responsive receiver a source of practically-constantvoltage,.and means for charging and discharging the discharge-gapcircuit without an appreciable time interval betweenthe'charging anddischarging.

25. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor operatively connected to a discharge-gap, asource of continuous current, a current-operated receiver and means forcharging and discharging the discharge-gap circuit without anappreciable time interval between the charging and discharging.

26. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor operatively connected to a discharge-gap, asource of practically-constant voltage, a current operated receiver andmeans for charging and discharging the discharge gap circuit without anappreciable time interval between the charging and discharging.

27. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor operatively connected to a discharge-gap, acumulative receiver, a source of continuous current and means forcharging and discharging the discharge-gap circuit without anappreciable time interval between the charging and discharging.

28. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor operatively connected to a discharge-gap, acumulative receiver, a source of practically-constant voltage and meansfor charging and discharging the discharge-gap circuit withoutappreciable time interval between the charging and discharging.

29. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a source of continuous current, a tuned circuitat the receiving end and means for charging and discharging theradiatingconductor without disconnecting the source of voltage.

30. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a source of practically-constant voltage, atuned circuit at the receiving end and means for charging anddischarging the radiating-conductor Without disconnecting the source ofvoltage.

31. ,In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a spark gap, a capacity and a source ofcontinuous current with a high resistance, whereby an intermittentdischarge across the spark-gap having a practically-constant periodicitymay be produced, substantially as set forth.

32. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a spark gap, a capacity and a source ofpractically-constant voltage, with a high resistance, whereby anintermittent discharge across the sparkap having a practically-definiteperiodicity may be produced, substantially as set forth.

33. In asystem of signaling by electroma netic waves, the combination ofa radiatingconductor, a spark-gap, one terminal of the spark-gap beingconnected to ground, a capacity and a source of practically-constantvoltage with a highlresistance, whereby an intermittent discharge acrossthe spark-gap havingapractically-constant periodicity may be produced,substantially as set forth.

34. In a system of signaling by electroma netic waves, the combinationof a radiatingconductor, a normally insulating dischargegap, a source ofcontinuous current connected thereto and means for causing the dischargeacross the discharge-gap to have a practicallyconstant periodicity,substantially as set forth.

35. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a normally insulating dischargegap, a source ofpractically-constant voltage connected thereto and means for causing thedischarge across the discharge-gap to have a practically-constantperiodicity,substantiall y as set forth.

36. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor having one terminal connected to ground, anormally insulating discharge-gap, a source of continuous currentconnected thereto and means for causing the number of discharges acrossthe discharge-gap to be practically constant, substantially as setforth.

37. In a system of signaling byelectromagnetic waves, the combination ofa radiatingconductor having one terminal connected to ground, a normallyinsulating discharge-gap, a source of voltage connected thereto andmeans for causing the number of discharges across the discharge-gap tobe practically consiant, substantially as set forth.

38. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a normally insulating dischargegap, a source ofcontinuous current connected thereto and meansfor causing any desirednumber of discharges per second across the discharge-gap, substantiallyas set forth.

39. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a normally insulating dischargegap, a source ofpractically-constant voltage connected thereto andmeans for causing anydesired number of discharges per second across the discharge-gap,substantially as set forth.

4.0. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a normally insulating dischargeto bepractically constant, substantially as set forth.

v42. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a normally insulating dischargegap having oneterminal connected to ground, a source of continuous current connectedthereto and means for causing any desired number of discharges persecond across the discharge-gap, substantially as set forth.

43. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a normallyinsulating dischargegap having oneterminal connected to ground, a source of practically-constant voltageconnected thereto and means for causing any desired number of dischargesper second across the discharge-gap, substantially as set forth.

44. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a normally insulating dischargegap, a source ofcontinuous current connected thereto, a capacity and means whereby anydesired number of discharges per second across the discharge-gap may beproduced, substantially as set forth.

45. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a normally insulating dischargegap, a source ofpractically-constant voltage connected thereto, a capacity and meanswhereby any desired number of discharges per second across thedischarge-gap may be produced, substantially as set forth.

46. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor having one terminal grounded, a normallyinsulating discharge-gap, a source of continuous current connectedthereto, a capacity and means whereby any desired number of dischargesper second across the discharge-gap may be produced, substantially asset forth.

47. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor having one terminal grounded, a normallyinsulating discharge-gap, a source of practicallyconstant voltageconnected thereto, a capacity and means whereby any desired number ofdischarges per second across the discharge-gap may be produced,substantially as set forth.

48. In a system of signaling by electromagneticfwaves, the combinationof a radiatingconductor, a normally insulating dischargegap, a source ofpractically-constant voltage connected thereto, a capacity and ahigh'resistance, whereby intermittent discharges across thedischarge-gap may be produced, the number of discharges per secondacross the discharge-gap beingpractically constant, substantially as setforth.

49. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a normally insulating-gap, a capacity and asource of continuous current, and means for regulating the time ofcharging of the capacity whereby intermittent discharges across the gapmay be produced, substantially as set forth.

50. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a normally insulating-gap, a capacity and asource of practically-constant voltage, and means for regulating thetime of charging of the capacity whereby intermittent discharges acrossthe gap may be produced, substantially as set forth.

5].. In a system of signaling by electromagnetic waves, the combinationof a radiatingconductor, a normally insulating dischargegap, a source ofpractically-constant voltage connected thereto, a capacity and a highresistance, whereby intermittent discharges across the discharge-gap maybe produced, the number of discharges per second across thedischarge-gap being practically constant, substantially as set forth.

In testimony whereof I have hereunto set my hand.

REGINALD A. FESSENDEN.

Witnesses:

T. L. SOLATER, JESSIE E. BENT.

